A patient may for various reasons desire that the size of the teeth is increased or the shape and/or color of the teeth is changed. This can be the case when the length of the teeth has been reduced due to e.g. grinding the teeth in sleep (Sleep Bruxism), or when the patient wishes to improve the aesthetic appearance of his teeth.
When a patient has worn his teeth down to an extent where it causes the patients occlusion to be disrupted, the result may be that the patient begins to experience problems in his temporomandibular joint (TMJ). Such problems may be solved by raising the bite such that a correct height of his occlusal table and hence a correct movement of the TMJ is restored. The bite can be raised using a set of table-top teeth arranged at the occlusal surface or incisal edge of the patient's teeth to replace the defective occlusal table of the patient's worn teeth. The phrase “raising the occlusal surface/incisal edge of a tooth” refers to the situation where the occlusal surface/incisal edge of the tooth is moved further away from the cervical/apical part of the tooth. I.e. when the patient's bite is raised the distance between the mandibular and maxillary jaw bones in occlusion is increased.
The table-top restoration preferably has a plurality of teeth covering at least the occlusal table of the worn teeth but the table-top restoration does not necessarily cover the entire labial/buccal and lingual surfaces of the patient's teeth.
The table-top teeth restoration does not necessarily require that the patient's teeth are prepared in order to allow the table-top restoration to be seated at the teeth. Especially for a temporary table-top restoration it may be advantageous to avoid extensive preparation of the patient's teeth until the bite has been raised, i.e. until the patient has become used to the corrected bite movement.
In prior art CAD software for designing dental restorations, the user must manually set the restoration margin line. The restoration margin line can be set using e.g. a computer mouse to mark relevant points on a digital 3D representation of the patient's teeth visualized on e.g. a computer screen.
Digital design of dental restorations, such as dental crowns or bridges, is often based on a digital 3D representation of the patient's teeth obtained after the teeth has been prepared for accepting the dental restoration. The preparation often occur by the dentist grinding away tooth material to realize a tooth stump, as so-called preparation, onto which the dental restoration can be seated. A restoration margin line is set e.g. from the tooth preparation line of the prepared tooth in the digital 3D representation. The operator then creates the digital restoration design from the restoration margin line e.g. by modifying a library tooth to have the set restoration margin line.
It remains a problem to provide a method, a user interface, and a system for creating digital restoration designs where the operator does not need to set the restoration margin line manually.